Do you link GoogleFonts on EVERY html page, or can you save time by incorporating these href links into the stylesheet?

You can embed the font CSS into your own using an @import statement at the top of your CSS file. Like this for example:

@import url('https://fonts.googleapis.com/css?family=Roboto');

However doing so can slow down your page load.

The reason for this is that when you use @import your browser will download and process the font CSS first and then process your CSS. When you use separate link elements for the font and for your own CSS on the other hand the browser will download and process both of the CSS files concurrently. Meaning that it does not wait for one before it starts working on the other.

Processing the CSS concurrently speeds up loading and rendering of the page, and due to this use of the @import statement is generally discouraged nowadays. So it's a trade off between convenience and speed. If including the font link on all of your pages is a large inconvenience for you then it might be worth a small processing delay to just use @import.